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Home > Articles > Variable Valency: Definitions, Examples, Electrovalency, Causes, Facts, and Sample Questions
Updated on 21st June, 2023 , 6 min read
Elements rarely exist alone in nature; instead, they interact with one another. Valency is the capacity of one element to mix with another. Elements interact with one another to produce a stable state. It specifies the maximum number of electrons that an element may accept or give in order to achieve a stable electronic state.
G.N. Lewis, a chemist, created Valency. An element's valency is its ability to combine. The amount of electrons provided or absorbed by an element's atom in order to have the electronic configuration of the next noble gas is referred to as its valency.
Certain components have several valencies; these are known as variable valencies; compounds of this type have varying valencies in different combinations. Iron, mercury, and copper are examples of elements with varying valency. Transition elements are characterized by varying degrees of valency. Depending on the sort of interaction, different elements interact with other atoms in varying quantities, receiving, giving, or sharing electrons with them. The varieties of valency are as follows-
When iron combines with oxygen, for example, it produces ferrous oxide and ferric oxide, among other molecules. Variable valency is the name given to this occurrence. Transition metals with varying valencies include nickel, copper, tin, and iron.
Ionic bonds are formed when electrons are lost or added to an element's atom. This is referred to as the element's electrovalency. The s-block components have no changeable valency. The valency of P-block elements with higher atomic numbers and transitional inner elements is more varied. There are two major causes for varying valency. Inert pairs' effect on p-block elements. When it comes to inner transition elements, the energy difference between ns and (n-1) d subshells, as well as ns and (n-2) d subshells, is quite small.
The oxidation state of the bulk of the elements in the III-A group is +3. However, as we progress through the group, the oxidation state +1 becomes more dominant. Similarly, the elements in the IV A group have a +4 oxidation potential in general, but as we descend the group, the +2 state becomes more dominant. The two electrons in the valence shell (ns2) tend to stay inactive when bonds are formed. This is known as the inert pair effect. As a result, inert pair effects are the principal cause of changing valency in p-block elements.
The fluctuation of incompleted orbitals and electrons from the ns orbital in transition metals causes the oxidation state to vary. As a result, electrons from both energy levels can be bonded. Similarly, the valency of inner transition elements varies due to insufficient filling of f-orbitals. In addition to ns electrons, some f-orbitals can be used to form chemical bonds.
The following are some of the causes of variable valency-
Transition metals with varying valencies include nickel, copper, tin, and iron. Non-metallic elements with variable valencies include nitrogen and oxygen. When various valency atoms react, the products they form have varied qualities. The following table gives details about the various elements having variable valency-
Copper (Cu) is available in two forms- |
|
Cuprous (Cu ⁺²) |
Cupric (Cu ⁺³) |
Iron (Fe) is available in two forms- |
|
Ferrous (Fe ⁺²) |
Ferric (Fe ⁺³) |
Mercury (Hg) is available in two forms- |
|
Mercurous (Hg ⁺¹) |
Mercuric (Hg ⁺²) |
Silver (Ag) is available in two forms- |
|
Argentous (Ag ⁺¹) |
Argentic (Ag ⁺²) |
It is usual to employ a Roman number as a superscript next to an element's symbol to denote its changeable valency. For metals, the suffix 'ous' represents the lower valency, while the suffix 'ic' represents the greater valency, in this order-
For example, the valency of iron is between two and three. As a result, we write ferrous (Fe²⁺) to represent the lower valency (2), and ferric (Fe³⁺) to indicate the higher valency (3).
The current technique, on the other hand, employs Roman numerals to describe an element's changeable valency. As a result, we use Fe (II) for ferrous and Fe (III) for ferric.
The valency of a nonmetal is dictated by the number of other atoms connected to it. Phosphorus and potassium, for example, contain three and five valence electrons, respectively. It forms two molecules when coupled with chlorine-
In the structure of phosphorous trichloride, three electrons are shared by phosphorous and three chlorine atoms, resulting in the element possessing valency 3. Because pentachloride possesses five electrons, it has a valency of five.
A particular element's valency can alter depending on the circumstances of a chemical reaction. Metals, in general, donate electrons from their outer shells to produce positively charged ions. Some metals' valence shells, on the other hand, lose electrons. The element in this situation has a variable number of valence electrons and different electropositive valencies.
Solution: It is indeed. It has two values: 1 and 3.
Solution: Iodine has an electron-accepting propensity. It has a valency of 1.
Solution: The ability of elements to represent multiple valencies in distinct compounds is referred to as variable valency. Variable valency, as the name implies, lacks a defined pattern. The electrical configuration of any element is required to get its variable valency. Variable valency occurs when a chemical has various vacancies.
Solution: The two components are iron and silver.
Solution: Argon has no valency.
Solution: Iron has a more stable valency of three. Because the d - blocks are half-filled, they have a greater probability of forming a robust configuration, making the configuration stable.
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By - Nikita Parmar 2024-09-06 10:59:22 , 6 min readAns. Because the phosphorus valence is 3, they will increase their valence owing to the unoccupied d orbital. It should be three since phosphorus has five electrons in its valence shell. As a result, it absorbs three electrons and completes its bit, since accepting three electrons is considerably easier than giving five electrons.
Ans. Valence electrons are the electrons that exist in an atom’s outermost shell. As a result, one or more electrons from the core’s outermost shell may be lost when valence electrons are removed. As a result, such items have variable valentia since they have two or more different valencies.
Ans. The valence value of oxygen is 2. Because it is 2,6, it just needs two more electrons to finish it as an octet. Valence is equal to n for elements with n = 1, 2, 3, and 4 electrons in the outer shell, but 8-n for elements with n = 5, 6, and 7 electrons in the outer shell.
Ans. The valence of an element is known as its combining power. The capacity of some elements to interact with other elements varies depending on the nature of the interaction; this trait is known as variable valence. For example, iron (Fe) can have valences of 2 and 3.
Ans. Depending on the nature of the reaction, some elements combine with other atoms to donate, take, or exchange electrons in varying amounts. To begin, iron reacts with oxygen to generate ferrous oxide and ferric oxide. It is known as the valence element.